Which statement about Giardia lamblia cysts is true?

Which statement about Giardia lamblia cysts is true?

• A. They are motile by flagella
• B. Contain four nuclei
• C. Have an undulating membrane
• D. Are rarely found in stool specimens

Answer: (B)

Giardia lamblia alternates between a motile trophozoite and a resistant cyst. The cyst stage is the infectious form that is typically sought in stool for diagnosis. A key identifying feature of mature Giardia cysts is that they contain four nuclei, which is why this statement is true. The cyst form is non-motile and lacks an undulating membrane; those traits belong to the trophozoite. Additionally, cysts are commonly found in stool when Giardia infection is present, so saying they are rarely found is not accurate.

Giardia lamblia alternates between a motile trophozoite and a resistant cyst. The cyst stage is the infectious form that is typically sought in stool for diagnosis. A key identifying feature of mature Giardia cysts is that they contain four nuclei, which is why this statement is true. The cyst form is non-motile and lacks an undulating membrane; those traits belong to the trophozoite. Additionally, cysts are commonly found in stool when Giardia infection is present, so saying they are rarely found is not accurate.